1. Field of Invention
The present invention relates to power distribution for high-frequency lighting systems.
2. Description of Prior Art
High-frequency lighting systems have been described in several prior art references, such as for instance in U.S. Pat. No. 4,207,497 to Capewell et al, or in U.S. Pat. No. 4,207,498 to Spira et al. In all of these systems, high-frequency power is distributed in the same fashion as is conventionally done with ordinary low-frequency power supplied directly from the power line. That is, the high-frequency power is distributed from its source to the various high-frequency lighting fixtures by way of a single set of high-frequency conductors--with the fixtures connected with these conductors at spaced-apart points therealong. Thus, the conductors have to have a length that extends to the fixture that is furthermost removed from the power supply. Moreover, especially near the source, the conductors have to carry a relatively heavy current--substantially more current than is required by a single lighting fixture.
Due to skin effect, which is indeed very much in evidence at the power levels and at the 20-40 kHz frequencies typically used with high-frequency lighting systems, it is necessary--in order to keep distribution losses within acceptable levels --to provide for special and costly distribution conductors. Or, it is necessary to accept higher-than-normal distribution losses.
Also, due to the resulting relatively high product of high-frequency current and conductor length, a correspondingly high degree of radiation of radio frequency interference results.
Moreover, the conventional fixture-to-fixture or serial method of power distribution provides for a relatively inflexible relationship between the various lighting fixtures, making it particularly difficult to move on fixture relative to another.